The conduct of business today requires the generation, handling, and processing of vast quantities of documents. The information on many of these documents must be read and understood, and then processed for further action depending upon the information on the document. By way of example, a banking check may have to be read and processed further to properly debit the account of the payee. Or, the address on a mailing envelope, including a zip code, may have to be read before the envelope is forwarded to its proper bin for distribution. Various automatic reading apparatus have been developed, including bar code reading equipment, magnetic-ink character reading devices, optical scanners, and the like, to increase the speed at which documents are processed. As the procedures related to reading and handling of documents have decreased the time necessary to interpret documents, the speed at which such documents can be passed through document handling apparatus has increased. Document handling apparatus has been developed to automatically and rapidly transmit documents, one at a time, from a storage station, through a transport station, and to a further processing station, for example, a document indicia reading station.
Some presently available document handling apparatus of the type referred to herein utilize document feed systems comprising intermittently driven roller devices at the end of a spring loaded horizontally disposed stack of documents, for example, to feed documents, preferably one at a time, from the end of the stack to the next work or processing station. Since many of the documents in the stack, such as checks, envelopes, or the like, may be of different sizes or paper quality, and have different effective coefficients of friction between adjacent pairs of documents, it is often difficult to ensure the feeding of one document at a time from the stack. Part of this problem is caused by the fact that certain stack feed mechanisms do not provide an efficient means for moving the stack as a unit thus improving the frictional force with which the feed roller can drive the document out of the stack.
In addition, currently available feed tray mechanisms of the type described do not provide a document feed station wherein a large stack of documents is fed in a feed tray by a system of underlying belts at a constant speed towards the feed roller, with a substantial force applied to the rear of the larger stack to move the documents forward in the feed tray, and thereafter progressively decreasing this force as the size of the stack of documents changes. If a force is not constantly applied to the back support plate urging the documents forward, a gap forms between adjacent documents, thereby disabling the feed roller mechanism disposed in the front plate of the feed tray.
An object of the present invention is to provide a document feed drive mechanism, which moves the feeder stack substantially as a unit, with a substantially increased surface area, whereby the frictional contact between the feed drive mechanism and the documents is increased.
Another object of the present invention is to provide a feed mechanism for moving a lengthy stack of documents vertically aligned at a feed station, wherein the feed mechanism maintains an initial substantial force on the rear of the lengthy stack of documents and then progressively decreases the force on the stack as the size of the stack decreases to prevent gaps from forming between documents as they move forward in the feed station.
A further object of the present invention is to provide a feed mechanism for advancing documents in a lengthy stack of documents vertically aligned at a feed station, wherein the feed station includes a belt system underlying the document stack which drives the documents forward to a document removal assembly at a constant speed, and further includes a movable back-up plate which advances at the same speed as the movement of the belt system, while at the same time provides a variable compressive force to the stack of documents remaining in the feed station.